Treatment of hydrocarbons



Sept. 4, 1945. D. .REAQJRv 2,384,339

TREATMENT OF HYDQCARBONS Filed Aug. 3o, 1945 EATMENT F ROCARBON SApplication August 30, 1943, Serial No. 500,535

(ci. 19e- 52) 9 Claims.

invention relates to the treatment or" hydrocarbons and moreparticularly to a combina-z tion process comprising a series ofinterdependent and cooperative steps :for the production of gasoline oihigh antiknock characteristics and low bromine number, which gasoline isparticularly suitable for use in aviation fuel.

In a broad aspect the present invention relates to a process forproducing gasoline of high antiknock characteristics and low brominenumber, which comprises separating an olelnic gasoline into a lightfraction and a heavy fraction, catalytically retreating the lightfraction in the presence of a phosphoric acid catalyst to produce aretreated fraction of relatively low brcmine number and at the same timeforming oienic hydrocarbons which are higher boiling than said lightfraction, hydrogenating said olenlc hydrocarbons, and blending atleast aportion of the hydrogenated products with said retreated fraction ofrelatively low bromine number.

In one specific embodiment the present invention relates to a processfor the production of gasoline of high antiknock characteristics and lowhromine number, which comprises subjecting oil to catalytic cracking toproduce gasoline, separating the gasoline from normally gaseoushydrocarbons and from 'higher boiling insumciently converted products,further separating said gasoline into a light fraction having an endboiling point within the range of from about 200 to about 300 F. and aheavy fraction hav- -ing an initial boiling point Within the range offrom about 200 to about 300 F. and an end boiling point within the rangeof from about 300 to about 400 F., subjecting the light gasolinefraction to retreatment in the presence of a phophoric acid catalystunder conditions to form a retreated light gasoline fraction having alower bromlne number and at the same time forming olenic hydrocarbonshaving an initial boiling point above from about 200 to about 300 F.,subjecting at least a portion of said oleflnic hydrocarbons tohydrogenation to form parafnic hydrocarbons, and blending at least aportion of said paralnic hydrocarbons with at least a portlon oi' saidretreated light gasoline fraction of lower bromine number.

In accordance with the present invention, an oleflnlc gasoline fractionis subjected to retreatment in the presence of a. phosphoric acidcatalyst to form a retreated light gasoline fraction which is high inantikn'ock characteristics and low in bromine number. During suchtreatment, a fraction boiling above the range of said retreated lightfraction is formed and this higher boiling fraction is high in olenichydrocarbons. This higher boiling fraction is unsuitable for use inaviation gasoline because or' its high olen content and, as a feature ofthe present invention, it has been found that this higher boiling olenicfraction may be subjected to-hydrogenation to produce a substantiallysaturated product which is particularly suitable for blending with theretreated light gasoline fraction in order to form a nal gasolinefraction of desired boiling range which is ofexceptionally highantiknock characteristics, of vrelatively low brcmine number andtherefore particularly suitable for use in aviation gasoline.

The invention will be more fully described in connection with theattached diagrammatic flow drawing which illustrates several specicembodiments of the invention. It is understood,

however, that the broad scope of the present invention is not limited tothe particular embodiments illustrated in the drawing,

Referring to the drawing, the charging stock to the.process may compriseany ,suitable oil, which usually Wll be heavier than gasoline,l such askerosene, gas oil, fuel oil and the like. The charging stock isintroducedthrough line l and may be commingled with certain recyclestreams in a manner to be hereinafter described in detail, and thecommingled streams are supplied to cracking zone 2. Y

Cracking zone 2 may comprise any suitable cracking system for eiectingthe desired conversionoi the oil into gasoline. While anon-catalyticoperationl may be employed in certain cases, in thepreferred embodiment of the invention, zone 2 is preferably a catalyticcracking system. The catalytic cracking process may be of any suitabletype and this may comprise the so-called xed bed, uidized, slurry, othertypes of moving be'ds, or combinations thereof. Any suitable crackingcatalyst may be employed, the preferred catalyst comprisingsynthetically prepared composites of silica and alumina or othersuitable metal oxides. These catalysts are normally utilized attemperatures within the range of 800 to 1200 F. and preferably withinthe range of 950 to 1050 F., superatmospheric pressures of below aboutpounds per square inch and weight hourlyl space velocities which areusually above 1 and may in some cases be as high as 10 or even more. Byweight hourly space velocity is meant the weight of oil per hour perweight of `catalyst in the reaction zone. "I'he temperature, pressure,space velocity and the like are correlated in this step of the process tproduce a gasoline of high antiknocir characteristics. In order toobtain optimum conversions of-the charging oil into gasoline ofsumciently high antiknock characteristics, the resulting gasoline willof necessity be of higher oleiinic content than is permissible for usein aviation gasoline.

The cracked products are directed through line 3 into separation zone d,which may comprise one or a, plurality of suitable fractionating,absorbing or stripping zones, 'whereby the products introduced theretomay be separated into the desired fractions. In accordance with thepreferred embodiment of the invention, hydrocarbons boiling from about300 to about @00 F. are separated in zone 6 and are Withdrawn from thelower portion thereof through line E. These higher boiling products maybe removed from the process or all or a portion thereof may be recycledby way of lines 6 and I to zone 2 for further conversion therein.INorr'nally gaseous products may be withdrawn through line 'I from zone4 and may be removed from the process. These gases are high in olefiniccontent and therefore are particularly suitable for use in subsequentpolymerization, alkylation or other condensation reactions.

A'gasoline fraction which, as heretofore set forth, will have an endboiling point within the range of from about 300 to about 400 F.andpreferably in the neighborhood of 340 to 350 F., is withdrawn fromzone 4 through line 8 and is directed into separation zone 9, which maybe similar to heretofore described zone 4. In zone 9. the gasoline isseparated into a light fraction which will have an end boiling pointwithin the range of from about 200 to about 300 F. and

preferably in the neighborhood of about 250 F.,

and a heavy gasoline fraction which will have an initial boiling pointsimilar .to the end boiling point of the light fraction and an endboiling point within the range of from about 300 to about 400 F. `andpreferably within theneigh-borhood of about 340 to about 350 F. 'I'helight fraction may be withdrawn from zone 0 through line I0 for furthertreatment in accordance with the present invention, as will behereinafter described in detail, lwhile the heavy gasoline fraction iswithdrawn from the lower portion of zone 0 through line I I for furthertreatment as will likewise be hereinafter described in detail.

The light gasoline fraction withdrawn through line Il is directed intoretreating zone I2. Itetreating zone I2 may comprise any suitable Systemcontaining a phosphoric acid catalyst for reducing the bromine number ofthe light gasoline,

fraction introduced thereto while, at the same time, forming a higherboiling product which is olennic in nature. According to the preferredembodiment of the invention, zone I2 comprises a retreatment zone inwhich the gasoline is contacted with an acid-acting compound ofphosphorus at a temperature of from about 250 to about 750' F. andpreferably of from about 350 to about 000 Il'. under sumcient pressureto maintain at least a substantial portion of the material in thereaction zone at the conditions of operation in liquid phase. Such aprocess is usually conducted at a weight hourly space velocity of fromabout 0.5 to about 10. satisfactory but not necessarily equivalentcatalysts include ortho-phosphoric acid, pyro-phosphoric acid, copperpyrophosphate, cadmium. pyro-phosphate, etc., which may be employedeither alone but .preferably in assenso admixture with a suitablesupporting material, such as kieselguhr, pumice, bentonite, bauxite, andother siiiceous and aluminiferous materials, to form a solid phosphoricacid catalyst.

Another suitable method of operation, which is not necessarilyequivalent to that heretofore described, is to subject the gasoline tocontact with a silica base catalyst under selected conditions ofoperation. The silica base catalyst may be similar to or different thanthe preferred cracking catalyst employed in zone 2 and likewise ispreferably synthetically prepared although certain natural occurringmaterials may .be employed but not necessarily with equivalent results.These catalysts are usually employed at temperatures of between about400 and about r100" F. under sulcient pressure to maintain at least asubstantial portion of the material in the reaction zone in liquidphase. The weight hourly space velocities may be within therange of fromabout 0.3 to 5. The temperature, space velocity and other conditions ofoperation are correlated in order to produce a nal gasoline productwhich .is low in bromine number. Preferably, the bromine numvber isreduced to less than one-half that of the light gasoline fractionintroduced through line I0 into zone i2.

The products from zone I2 are directed through line I3 into separationzone I4, which may be similar to heretofore described zones 4 or 9. Inzone I4 a light gasoline fraction, which is high in antiknockcharacteristics and low in bromine number, is separated and is withdrawntherefrom through line I5 and may be removed from the process butpreferably, in accordance with the features of the present invention, atleast a p0rtion thereof is directed through line I8 for blending withcertain other products of the process in the manner to be hereinafterdescribed in detail. This light fraction will have an end boiling pointwithin the range of from about 200 to about 300 F. and preferably withinthe neighborhood of about 250 F.

As a feature of the present invention, an intermediate fraction boilingabove the light gasoline fraction withdrawn through line I5 and havingan end boiling point within the range of from about 300 to about 400 F.and preferably within the neighborhood oflabout 340 to about 350"` F.,is separated in zone I4 and is withdrawn therefrom through line I1. Thisintermediate fraction is too high in olefin content for use in aviationgasoline and, in accordance with the present invention, it is subjectedto lfurther treatment in the manner to be hereinafter described indetail. Hydrocarbons boiling above the intermediate fraction withdrawnthrough line I1 are seperated in zone I4 and are withdrawn therefromthrough line I8 and maybe removed from the process through line Il, butpreferably at least a portion thereof is directed 'by way of lines 20, 0and I to zone 2 for further conversion therein. i

The intermediate fraction withdrawn through line I1 is commingled'withhydrogen introduced through line 2I and the mixture is directed intohydrogenation zonen. The fraction supplied to zone 22 will containaromatic hydrocarbons as well as oletinic hydrocarbons and hydrogenstionin zone 22 is preferably regulated in order to substantially hydrogenatethe oleflnic hydrocarbons without substantial hydrogenation of thearomatic hydrocarbons. This may be readily accomplished by the use ofparticular catalysts and by controlling the conditions of operation'.The

preferred catalyst comprises partially reduced nickel supported on arelatively inert carrier such as kieselguhr and the temperature employedis preferably below 400 F., although it is understood that highertemperatures may be employed if the other conditions of operation, suchas space velocity and pressure,y are correlated therewith in order toeffect the desired reaction.

.Hydrogenaton zone 22 may comprise any suitable hydrogenatlon systemwhich may be of the hxed bed or moving catalyst type. In the fixed bedtype of process, usually two or more zones are employed withcounter-current flow of hydrogen and hydrocarbons, although a'singlezone may be utilized 'when desired.

The hydrogenated products are directed from zone 22 through line it intoseparation zone 2li which may be similar to heretofore described zonesil, t or ifi. Since an excess of hydrogen is usually employed in thehz'drogenation reaction, unused hydrogen may be withdrawn through line2b from zone 2t and may be removed from the process but preferably atleast a portion thereof is recycled by way of lines 2li, iii and ll tozone d2 for further use therein. The hydrogenated products are withdrawnfrom the lower portion of zone 2d through line 2l and a portion thereofmay ce removed from the process while, in accordones with the presentinvention, at least a portion 'thereof is directed by way of line t8into line l@ wherein it is commingled with at least a portion of lightretreated gasoline withdrawn through line lll from .zone it. It has beenfound that blending oi the hydrogenated products with the light gasolineretreated `traction, in the manu ner herein described, produces agasoline produ uct ol exceptionally high antiknock characteristics andoi low bromine number which is par ticularly suitable ior use inaviation gasoline.

The heavy gasoline fraction separated in zone il and withdrawn therefromthrough line li may be directed, all or part, through line lil and maybe coninfiingled with the ilnal gasoline products in line The heavygasoline fraction withdrawn through line il will be high in aro maticcontent in many case-s will be suidle ciently 7ow in bron'iine number,so that it may be blend-eci without further treatment with the otherproducts oi the process in order to increase the yield of desiredaviation gasoline. In some cases, it is preferred to subject the heaviergasoline fraction to further treatment and this may be accomplished bysupplying the same through lin into retreating zone di. Retreatlng zoneSi may be similar to heretofore describedsone it and may utilize asimilar type ofcatalyst. lThe temperature employed in zone @l may be thesaine or slightly higher than that employed in zone is in order to eectthe desir ed reductionin bromuro num-ber and other improvements.

The products from zone 35 are then directed through line into separationzone 38 which may be similar to the heretofore described sepa@ ration.sones. ing an end boiling point within the range oi from about 3oii toabout 400 F., which end boiling point is preierably the same as the endboiling point ci? the gasoline in line it, may be separated in zone t3and withdrawn therefrom through line tl. A portion thereof may beremoved from the process throughvline Se but preferably all or a portionof this gasoline is directed throush line 'il and iS commillgled in linei@ with the inl gaioline product or the process. in this way, ad-

.u retreated gasoline fraction havA ditional yields of the desiredgasoline products are obtained.

Higher boiling products are separated in zone 33 and withdrawn therefromthrough line 36 and may be removed from the process but preferably atleast a portion thereof is directed by way of lines 20, G ard l intocracking zone 2 for further conversion t1 arein.

The following example is introduced for the purpose of furtherillustrating the novelty and utility of the present invention but notwith the intention oi unduly limiting the same.

A Mid-Continent gas oil is cracked in the presence of a silica-aluminacatalyst at a temperature of about 950 F. and an hourly weight spacevelocity of about 1.7. The products are separated by conventionalfractionation into a light gasoline fraction having an end boiling pointoi 250 F. and a heavy gasoline fraction having an initial boiling pointoi 250 F. and an end boiling point of 350 F.

The light gasoline fraction is subjected to retreatment in the presenceof a solid phosphoric acid catalyst at aA temperature ofA 525 F. and 500pounds per square inch, the solid phosphoric acid catalyst comprising amixture of ortho and pyro phosphoric acids composited with kieselguhr.rlhe retreated products are separated into a light fraction having anend boiling point of 250 F., an intermediate fraction having an initialboiling peint of 250 r. and an end honing point ci the finally blendedmaterial has an octane non L her ci above lo@ when determined accordingto the motor method.

i' claim as my invention:

l. A hydrocarbon conversion process which comprises treating an olelnlcgasoline with `a phosphoric acid catalyst under conditions to proa ducea light gasoline fraction of low bromuro number and a heavy olefinicfraction. of higher bromine number, hydrogenating at least a pora tionof said heavy olefinic fraction, and bleng at least a portion or" thehydrogenated products with said light gasoline fraction ci low broenumber.

2. A hydrocarbon conversion process which comprises treatingcraclredgasoline with a phosphono acid catalyst under conditions to produce .alight gasoline fraction oi low bromlne number and having an end boilingpoint within the range of from about 200 to about 300 F., and a heavyolei'tlnic traction oi higher bromine number hav;- ing an initialboiling point within the range oi from about 200 to about 300 F. and anend boiling point within the range oi from about 800 to about 400 F.,catalytically hydrogenating at least a portion of said heavy olefinicfraction, and blending at least a portiony of the hydrogenated productswith said-light gasoline fraction to produce a nal gasoline producthaving a bromine 'number of less than one-half that of said crackedgasoline.

3. A hydrocarbon conversion process which comprises cracking oil underconditions topraduce a cracked gasoline o! high antiknockcharacteristicsand high bromine number. separating said gasoline into light and heavyfractions, retreating said light fraction in the presence oi.' a

phosphoric acid catalyst under conditions to pro-- duce a light gasolinefraction of low bromine number and a heavier oletlnic fraction of higherbromine number, catalytically hydrogenatlng said heavier oleiinicfraction in the presence of added hydrogen, and blending atleast aportion oi' the hydrogenated products with said light gasoline fractionof low bromine numbe 4. The process oi claim 3 further characterized inthat at least a port-ion. .ofztiie'rst mentioned heavy fraction isblended with the retreated and hydrogenated products.

5. 'I'he process oi cl3 further-characterized in that at least a portionci rst mentioned :heavy the presence of a phosphoric acid catalyst, andat least a portion 4of the separately retreated products is blended`with the rst mentioned re treated and hydrosenated products. .Y

6. A hydrocarbon" conversion4 process which comprises catalyticailycracking` oil under conditions to produce a cracked gasoline ci highantiknock characteristics and high bromine number, separating saidgasoline into a light fraction' having an end boiling vu'itlniri the'rame oi from about 200 -to about 300 li. and vs heavy gasoline fractionhaving an initial boiling point within the range of from .about 300 l.toabout 300 F. and anend boiling point within the range of from 300 toabout 41.00 F., retreatingV said light fraction in the presence oi aphosphoric acid catalyst under conditions to produce a iight gasolinefraction of low bromine number and having an end boiling point withinthe raus@ oi' from about 200 to about Somitand a heavier oleilnicfraction oi .higher bromine number having an initial boiling pointwithin the .range oi from about 200.to about 300 El. and an end boilingpoint Within the range of from about 300 to about 400 F., hydrosenatingsaid heavier ole @nic fraction in the presence oi anickel hydrogenatingcatalyst and hydrogen, separating a range of from about 300 to about 400Il'. from the hydrogenated products and blending at least a portionlthereof with vsaid light gasoline iraction oi low bromine number.

7. A process for producing hydrocarbon distillate suitable for use inaviation fuel from the products of hydrocarbon oil cracking, whichcomprises separating irom said porducts an, olei'inic gasoline fractionhaving. an end boiling point in the approximate range of 200 F. to 300F.. contacting said gasoline fraction with a.. catalyst comprising anacid-acting compound oi phosphorus at a temperature of from about 250"lF.

to about 750 F. and at vaj weight hourly space velocity oi' from about0.5 toabout- 10, whereby to :reduce the bromine number of said fractionand form a heavier olennic fraction, separating said heavier oleiinictraction trom the lower boil- 20 fraction is subjected to separateretreatment in v ing sasoline fraction oi reduced bromine numberandhydrogenating at least a portion thereof to formparailnichydrocarbons, and blending at ,least a portion oi saidv parafnichydrocarbons fraction having an end boiling point Within the with atleast a portion of said gasoline fraction oi reduced bromide number.

0. A process Kor iiriprovirig cracked gasoline which comprisesseparatingthe same into a light oletinic traction and a heavier gasolinefraction, contacting said light fraction 'with acetalyst comprising anacid-acting compound oi phosphorus at a temperature of from about 250 F.Ato .about 350 if'. and at a weight hcuriepace yelocity-o from about 0.5to about i0, whereby to reduceL the bromine number of said fraction andform a heavier oiennic fraction, separating y said heavier olelnicfraction from the lower boiling gasoline fraction o reduced bromidenumber and hydrosenating at least a portion thereof to form parailinichydrocarbons. and blending regulated portions of said paralnichydrocarbons. said heavier gasoline fraction and said gasoline fractionci reduced ibromine number.

9. The process as defined in claim 8 further characterised in that saidheavier gasoline iractionis catalytically treated for reduction inbromine number prior tothe blendingthereoi with said parafiinichydrocarbons and easoiine iraction oi reduced bromine number.

